The present invention relates generally to magnetic recording tape guide assemblies, and more particularly, to a compact tape guide assembly with reduced lateral tape motion.
Magnetic media are used for storage of data generated by computers. Typically a magnetic medium is presented to a magnetic head which ordinarily can either read or write data on the medium. Magnetic storage disks, commonly referred to as hard disks, are presently the preferred storage medium for use in computer systems where fast access time and substantial storage capacity are of interest. But because of their low cost, portability, compactness and adequate storage capacity, magnetic tapes are also used for data storage.
One advantage which tapes have over hard disks is that once the data is on a magnetic tape, the tape and its container (commonly referred to as a cartridge) can be removed from the computer and stored in a secure location or can be used for carrying or mailing data to a remote location. This removable feature allows tape and tape drives to be used as archival storage and/or "back-up" systems for hard disks. However, the data error rate must be quite low to allow use as archival and/or backup storage devices.
In order to increase storage density for a given cartridge size, thinner tape may be employed. Also, bits may be written on the tape in smaller areas and on a plurality of parallel longitudinal tracks. As more tracks are recorded on a tape, each track then becomes narrower and the tape must now be constrained from shifting up or down (called lateral tape motion) in a direction perpendicular to the tape travel path as the tape passes by the magnetic head, so as to maintain proper alignment of the head and tracks on the tape, thus to prevent data retrieval errors.
Lateral tape motion is defined as the peak-to-peak distance of the undesirable movement (in-plane) of the tape perpendicular to its prescribed longitudinal direction of motion past the head. Lateral tape motion is a major contributor to tape reading error, and must be limited to a fraction of the track width so that readback amplitude is not lost if a written track fails to line up substantially with the transducing portion of the head. As well, if the data portion of the tape puckers or is otherwise not essentially straight and planar and presented at uniform tension as the tape contacts the transducing portion of the head, then data retrieval errors are likely to result.
The tape is presented to the head by a tape guide assembly in a tape drive assembly. The tape guide assembly must be capable of repeatedly and accurately presenting the tape to the head despite some wear in the tape, tape cartridge or tape guide assembly, or variations in tape width and straightness, as well as allowing for idiosyncrasies between various members of a computer family where a tape may be recorded in one member of a family and played back in another member of the family.
It is therefore an object of the present invention to provide a tape guiding system which minimizes lateral tape motion.
It is another an object of the present invention to provide a tape guiding system which minimizes lateral tape motion regardless of variations in the tape media, tape cartridge, or the tape drive assembly.